package eu.mikroskeem.utils.bukkit;

import eu.mikroskeem.utils.reflect.Reflect;
import org.bukkit.Bukkit;
import org.bukkit.plugin.java.JavaPlugin;
import org.bukkit.plugin.java.JavaPluginLoader;
import org.bukkit.plugin.java.PluginClassLoader;

import java.lang.reflect.Field;
import java.lang.reflect.Method;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;

import static com.google.common.base.Preconditions.checkNotNull;

public class ServerUtils {
    /**
     * Get server's TPS
     *
     * Will use PaperSpigot's API if available, reflection otherwise
     * @return double array of TPS (not rounded!), values are -1 if reflection failed
     */
    public static double[] getTPS(){
        if(Reflect.getMethod(Bukkit.class, "getTps") != null) {
            return Bukkit.getTPS();
        } else {
            try {
                Class<?> MinecraftServerClass = checkNotNull(Reflect.getClass(
                    String.format("net.minecraft.server.%s.MinecraftServer", getNmsVersion())));
                Method getServer = checkNotNull(Reflect.getMethod(MinecraftServerClass, "getServer"));
                Field recentTPS = checkNotNull(Reflect.getField(MinecraftServerClass, "recentTps"));
                Object server = checkNotNull(Reflect.invokeMethod(getServer, null));
                return (double[]) checkNotNull(Reflect.readField(recentTPS, server));
            } catch (NullPointerException ignored){}
        }
        return new double[]{-1, -1, -1};
    }

    /**
     * Get plugin class loader. Useful when you want to add new classes on runtime
     *
     * @param plugin Plugin which will be used to get plugin ClassLoader
     * @return Plugin ClassLoader
     */
    @SuppressWarnings("unchecked")
    public static ClassLoader getPluginClassLoader(JavaPlugin plugin){
        JavaPluginLoader pl = (JavaPluginLoader)plugin.getPluginLoader();
        Field loadersField = Reflect.getField(pl.getClass(), "loaders");
        if(loadersField != null) {
            List<PluginClassLoader> loaders = null;
            switch (getNmsVersion()){
                case "v1_8_R3":
                case "v1_9_R1": // TODO: Check?
                case "v1_9_R2":
                    loaders = new ArrayList<>(((Map<String, PluginClassLoader>)
                            Reflect.readField(loadersField, pl)).values());
                    break;
                case "v1_10_R1":
                case "v1_11_R1":
                    loaders = (List<PluginClassLoader>) Reflect.readField(loadersField, pl);
                    break;
            }

            if(loaders != null) {
                for(PluginClassLoader loader : loaders) {
                    if(loader.getPlugin().getName().equals(plugin.getName())){
                        return loader;
                    }
                }
            }
        }
        return null;
    }

    /**
     * Get NMS version of current running server
     * @return NMS version or 0 length string
     */
    public static String getNmsVersion(){
        try {
            String bukkitPackageName = Bukkit.getServer().getClass().getPackage().getName();
            return bukkitPackageName.substring(bukkitPackageName.lastIndexOf(".") + 1);
        } catch (NullPointerException e){
            return "";
        }
    }
}